Such a force accumulator for a load changeover switch is already known from DE-PS 19 56 369 as well as DE-PS 28 06 282 [GB 2,014,794]. It is loaded, i.e. stressed, at the start of each actuation of the on-load tap changer by the drive shaft thereof. The known force accumulator substantially consists of a pull-up carriage and a jump carriage between which force accumulator springs as force accumulators are arranged. In these known force accumulators guide rods are provided on which pull-up carriages as well as jump carriages are mounted to be movable therealong independently of one another. At the same time, the guide rods form the guide for the force accumulator springs.
The pull-up carriage is moved linearly relatively toward the jump carriage by an eccentric connected with the drive shaft; the force accumulator springs disposed therebetween are thereby stressed. When the pull-up carriage has reached its new end position, a locking, which until then is fixed, of the jump carriage is released. The jump carriage now abruptly follows—since it stands under the force of the force accumulator springs—the afore-mentioned linear movement of the pull-up carriage, similarly linearly. This abrupt movement of the jump carriage is converted into a rotational movement of a drive output shaft that in turn actuates the load changeover switch. An alternating to-and-fro switching between two positions is thus realized in this force accumulator.
A further force accumulator, there termed spring jump drive, is known from WO 19 9/008924 whose storage spring is stressable by a drive. In that case the driven element is connected with a special coupling element that can be triggered in only one direction regardless of the direction of rotation of the drive.
WO 2006/004527 [U.S. Pat. No. 7,982,142] relates to a further arrangement of that kind, in which the permanent main contacts of an on-load tap changer are actuated always in the same rotational direction, regardless of the drive direction of the drive shaft, by a special mechanical transmission.
A quite similar arrangement is known from WO 2007/067144 [U.S. Pat. No. 7,942,073]. A device for transmission of a rotational movement in a load changeover switch is described therein, wherein the rotational movement of a drive shaft, which is rotatable in both directions, is converted into a rotational movement of a drive output shaft always rotating in the same direction.
The force accumulators, which are known from the prior art, for an on-load tap changer of the above-described kind thus allow either to-and-fro switching in the case of switching processes taking place in succession or onward switching always in the same direction.